<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <script src=" https://code.angularjs.org/1.6.4/angular.js">

    </script>
</head>

<body>
    
    <div ng-app="myApp" ng-controller="personCtrl">
        名: <input type="text" ng-model="firstName"><br>
        姓: <input type="text" ng-model="lastName"><br>
        <br>
        姓名:{{fullName()}}
    </div>

    <script>
        var app=angular.module('myApp',[]);
        app.controller('personCtrl',function($scope){
           $scope.firstName="John";
           $scope.lastName="Doe";
           $scope.fullName=function(){
               return $scope.firstName+" "+$scope.lastName;
           }
        });
    </script>

</body>

</html>